Are Links Still a Powerful Search Ranking Factor?

If you’ve been following SEO for more than 15 years like I have, you’ve seen the ongoing debates about ranking factors go on seemingly forever. One of the latest themes is the decline of links as a ranking factor. Many theories have been offered about what’s replaced them, such as:

Social Media Signals

Clickthrough Rate in the Search Results

User Engagement

RankBrain

But links remain a very powerful ranking factor. Read on for data from three different sources that backs this up, including data from our newly published extensive study on how links impact rankings.

Moz Ranking Factors Survey

Every two years, Moz does a ranking factors survey of the top SEO practitioners, asking them to identify the most important factors. This survey gathers input from those that perform SEO work day in and day out. As a result, this is one of the best sources of empirical evidence. After all, these people are trying to drive rankings for their clients every single day. Here are the top few results shown in the last survey, which published in 2015:

As you can see, this pegs links as the top two factors, and by a decent margin to boot.

Stone Temple Consulting Case Studies

As a participant in that survey, I can tell you that I certainly ranked links as being among the very top factors as well. One reason for this is the experiences we have at Stone Temple Consulting, where over and over again, links drive rankings. We typically help clients get these links via high-end content marketing campaigns which focus on helping drive their reputation and visibility.

The results are stunning. Here is a sample of results from a wide mix of clients:

As you can see, the results are pretty powerful!

Our Link Study

These results already tell a compelling story, but we wanted to dig into this deeper. To do that, we did a detailed correlation study. We took 6,000 search queries and gathered data across the top 50 search results. We captured the rankings for each of the SERPs and used Open Site Explorer to capture the link data related to each of the ranking URLs. (Thanks also to Moz for providing us access to their awesome API for use in the study).

We looked at the data several different ways. In one view, we normalized the total number of links for each search result, so that the search position with the most links had a link count score of 1, and a search result with half the links would get a link score of 0.5, and so forth. We then summed the link scores across, so that we could see the total link scores for all the number 1 results, the total link scores for all the number 2 result, all the way through all 50 results.

We then calculated Pearson and Spearman correlations for those totals. Pearson and Spearman correlations provide a measurement of the strength of the relationship between two variables. Here are the resulting scores we obtained:

If you’re not familiar with correlations, those numbers mean there is an extremely strong correlation between links and rankings. Just to spot check the conclusion, we also took a look at the correlations by ranking positions in blocks of 10. We once again normalized the link totals, but this time looked at the total number of links to all of the top 10 positions, then the number of links to all the second 10 positions, then the third 10, and so forth. Here is what that correlation showed:

That is still a very strong Pearson correlation value, and a perfect Spearman correlation. Wow!

What Did We Learn About the Power of Links?

So now we have it three different ways, and they all tell us the same thing: Links remain a very powerful ranking factor. But this doesn’t mean they are the only thing. Content relevance and quality are huge factors as well. If the content isn’t relevant, it shouldn’t matter how many links it has—it shouldn’t rank. If it’s relevant but of really poor quality, it shouldn’t rank, either.

There are other aspects of SEO that you can’t ignore, either, such as your overall information architecture, your site usability, how users engage with your content, and whether you need to be using SEO tags, such as rel=canonical, noindex, rel prev/next, and others.

That said, links remain a very important ranking factor, so promote your business in a way that will get it lots of recognition (and links) in the process. Stay away from the link schemes, of course, and focus on attracting the most high quality links that will stand the test of time.

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Eric Enge is the CEO of Stone Temple Consulting, a 70+ person digital marketing agency that serves Fortune 500 companies and other large enterprises. Eric regularly contributes to Forbes, Search Engine Land, The Digital Marketing Excellence blog, Copyblogger, Social Media Today, and other sites. He is lead co-author of The Art of SEO and is a regular speaker at many different digital marketing conferences.

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